The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
There are numerous events held with participants in water many of which are timed events. These include swimming races, surfboarding, and powered equipment events. Often the participants in these events are positioned in the water and are required to traverse a course or path in the water, or travel between two or more points or demarcation lines that are partially or wholly in the water. When timing many sporting events, such a running and biking events, it has become very common to use passive RFID tags for identifying the participant and the proximity of the participant to a monitored demarcation line or milestone such as a starting line, split point, turning point or finish line, by way of example. In such systems, the RFID tags are placed on a participant, on their clothing or a bib, or on the participant's vehicle for uniquely identifying the participant and for identifying the passing of the participant at the monitored point. For land based events, the RFID tag readers can easily be placed on a surface along the road or path for such sporting events even where there are numerous participants making a passing such as during a marathon race. For example, at a start of a marathon race, nearly all of the participants pass the starting line within a very short period of time. In such situations, one or more RFID tag readers with one or more RF antennas are placed at that starting line or are multiple points relative to the starting line to ensure that all participants' tags are read and the timing system logs their passing and the time of their individual passing.
However, for aquatic events, RFID tags and RFID tag readers have not been used with success. This is due to the RF absorption qualities of water, the position of the passive RFID tag on the participant or participant vehicle that may be at or near or under the surface of the water, or which may be immersed or covered with water at the time of the passing of the participant at a timed point at which the RFID tag reader is attempting to read the RFID tag of the participant. Additionally, the timing point readers would often be required to be placed in the water at the water located timing point. Due to these factors, the use of RFID tags and RFID tag readers for timed event systems has been extremely limited and often not used. Further, where attempted, it has been found to be very difficult to nearly impossible to stabilize the RF tag readers and their antennas in the water so as to consistently perform RF tag reads to the water located RFID tags that are approaching and passing the timing point. This is particularly true where there have been numerous to large number of RFID tags to be read that often requires sufficient advancing distances so as to not interfere with the participants and that provide for the desired accuracy of tag reads such that nearly all if not all participant tags are read and there are no missed tags. Further, the surface positioning of the RFID tag readers and in particular their RFID antenna are often moving due to changes in the surface and water flow conditions of the water, such as waves that may be due to displacement of the water by the participants or other sources including the wind and the tide.